1. Field of the Invention
The present invention relates to crystalline forms of anti-lipid antibodies, methods of making them, and methods of using data derived therefrom in antibody design and optimization. Methods for designing antibodies or antibody fragments are provided, wherein the antibody target is a lipid, such as a bioactive lipid.
The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein, or any publication specifically or implicitly referenced herein, is prior art, or even particularly relevant, to the presently claimed invention.
2. Background
Bioactive Signaling Lipids
Lipids and their derivatives are now recognized as important targets for medical research, not as just simple structural elements in cell membranes or as a source of energy for β-oxidation, glycolysis or other metabolic processes. In particular, certain bioactive lipids function as signaling mediators important in animal and human disease. Although most of the lipids of the plasma membrane play an exclusively structural role, a small proportion of them are involved in relaying extracellular stimuli into cells. “Lipid signaling” refers to any of a number of cellular signal transduction pathways that use cell membrane lipids as second messengers, as well as referring to direct interaction of a lipid signaling molecule with its own specific receptor. Lipid signaling pathways are activated by a variety of extracellular stimuli, ranging from growth factors to inflammatory cytokines, and regulate cell fate decisions such as apoptosis, differentiation and proliferation. Research into bioactive lipid signaling is an area of intense scientific investigation as more and more bioactive lipids are identified and their actions characterized.
Examples of bioactive lipids include the eicosanoids (including the cannabinoids, leukotrienes, prostaglandins, lipoxins, epoxyeicosatrienoic acids, and isoeicosanoids) such as the hydroxyeicosatetraenoic acids (HETEs, including 5-HETE, 12-HETE, 15-HETE and 20-HETE), non-eicosanoid cannabinoid mediators, phospholipids and their derivatives such as phosphatidic acid (PA) and phosphatidylglycerol (PG), platelet activating factor (PAF) and cardiolipins as well as lysophospholipids such as lysophosphatidyl choline (LPC) and various lysophosphatidic acids (LPA). Bioactive signaling lipid mediators also include the sphingolipids such as sphingomyelin, ceramide, ceramide-1-phosphate, sphingosine, sphingosylphosphoryl choline, sphinganine, sphinganine-1-phosphate (Dihydro-S1P) and sphingosine-1-phosphate. Sphingolipids and their derivatives represent a group of extracellular and intracellular signaling molecules with pleiotropic effects on important cellular processes. Other examples of bioactive signaling lipids include phosphatidylserine (PS), phosphatidylinositol (PI), phosphatidylethanolamine (PEA), diacylglyceride (DG), sulfatides, gangliosides, and cerebrosides.
Sphingolipids are a unique class of lipids that were named, due to their initially mysterious nature, after the Sphinx. Sphingolipids were initially characterized as primary structural components of cell membranes, but recent studies indicate that sphingolipids also serve as cellular signaling and regulatory molecules (Hannun, et al., Adv. Lipid Res. 25:27-41, 1993; Speigel, et al., FASEB J. 10:1388-1397, 1996; Igarashi, J. Biochem 122:1080-1087, 1997; Hla, T. (2004). Semin Cell Dev Biol, 15, 513-2; Gardell, S. E., Dubin, A. E. & Chun, J. (2006). Trends Mol Med, 12, 65-75). Sphingolipids are primary structural components of cell membranes that also serve as cellular signaling and regulatory molecules (Hannun and Bell, Adv. Lipid Res. 25: 27-41, 1993; Igarashi, J. Biochem 122: 1080-1087, 1997). The sphingolipid signaling mediators, ceramide (CER), sphingosine (SPH) and sphingosine-1-phosphate (S1P), have been most widely studied and have recently been appreciated for their roles in the cardiovascular system, angiogenesis and tumor biology (Claus, et al., Curr Drug Targets 1: 185-205, 2000; Levade, et al., Circ. Res. 89: 957-968, 2001; Wang, et al., J. Biol. Chem. 274: 35343-50, 1999; Wascholowski and Giannis, Drug News Perspect. 14: 581-90, 2001; Spiegel, S. & Milstien, S. (2003). Sphingosine-1-phosphate: an enigmatic signaling lipid. Nat Rev Mol Cell Biol, 4, 397-407).
For a review of sphingolipid metabolism, see Liu, et al., Crit. Rev. Clin. Lab. Sci. 36:511-573, 1999. For reviews of the sphingomyelin signaling pathway, see Hannun, et al., Adv. Lipid Res. 25:27-41, 1993; Liu, et al., Crit. Rev. Clin. Lab. Sci. 36:511-573, 1999; Igarashi, J. Biochem. 122:1080-1087, 1997; Oral, et al., J. Biol. Chem. 272:4836-4842, 1997; and Spiegel et al., Biochemistry (Moscow) 63:69-83, 1998.
Sphingosine-1-Phosphate (S1P)
S1P is a mediator of cell proliferation and protects from apoptosis through the activation of survival pathways (Maceyka, et al. (2002), BBA, vol. 1585): 192-201, and Spiegel, et al. (2003), Nature Reviews Molecular Cell Biology, vol. 4: 397-407). It has been proposed that the balance between CER/SPH levels and S1P provides a rheostat mechanism that decides whether a cell is directed into the death pathway or is protected from apoptosis. The key regulatory enzyme of the rheostat mechanism is sphingosine kinase (SPHK) whose role is to convert the death-promoting bioactive signaling lipids (CER/SPH) into the growth-promoting S1P. S1P has two fates: S1P can be degraded by S1P lyase, an enzyme that cleaves S1P to phosphoethanolamine and hexadecanal, or, less common, hydrolyzed by S1P phosphatase to SPH.
The pleiotropic biological activities of S1P are mediated via a family of G protein-coupled receptors (GPCRs) originally known as Endothelial Differentiation Genes (EDG). Five GPCRs have been identified as high-affinity S1P receptors (S1PRs): S1P1/EDG-1, S1P2/EDG-5, S1P3/EDG-3, S1P4/EDG-6, and S1P5/EDG-8 only identified as late as 1998 (Lee, et al., 1998). Many responses evoked by S1P are coupled to different heterotrimeric G proteins (Gq-, G1, G12-13) and the small GTPases of the Rho family (Gardell, et al., 2006).
In the adult, S1P is released from platelets (Murata et al., 2000) and mast cells to create a local pulse of free S1P (sufficient enough to exceed the Kd of the S1PRs) for promoting wound healing and participating in the inflammatory response. Under normal conditions, the total S1P in the plasma is quite high (300-500 nM); however, it has been hypothesized that most of the S1P may be ‘buffered’ by serum proteins, particularly lipoproteins (e.g., HDL>LDL>VLDL) and albumin, so that the bio-available S1P (or the free fraction of S1P) is not sufficient to appreciably activate S1PRs (Murata et al., 2000). If this were not the case, inappropriate angiogenesis and inflammation would result. Intracellular actions of S1P have also been suggested (see, e.g., Spiegel S, Kolesnick R (2002), Leukemia, vol. 16: 1596-602; Suomalainen, et al (2005), Am J Pathol, vol. 166: 773-81).
Widespread expression of the cell surface S1P receptors allows S1P to influence a diverse spectrum of cellular responses, including proliferation, adhesion, contraction, motility, morphogenesis, differentiation, and survival. This spectrum of response appears to depend upon the overlapping or distinct expression patterns of the S1P receptors within the cell and tissue systems. In addition, crosstalk between S1P and growth factor signaling pathways, including platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and basic fibroblastic growth factor (bFGF), have recently been demonstrated (see, e.g., Baudhuin, et al. (2004), FASEB J, vol. 18: 341-3). The regulation of various cellular processes involving S1P has particular impact on neuronal signaling, vascular tone, wound healing, immune cell trafficking, reproduction, and cardiovascular function, among others. Alterations of endogenous levels of S1P within these systems can have detrimental effects, eliciting several pathophysiological conditions, including cancer, inflammation, angiogenesis, heart disease, asthma, and autoimmune diseases.
A recent novel approach to the treatment of various diseases and disorders, including cardiovascular diseases, cerebrovascular diseases, and various cancers, involves reducing levels of biologically available S1P, either alone or in combination with other treatments. While sphingolipid-based treatment strategies that target key enzymes of the sphingolipid metabolic pathway, such as SPHK, have been proposed, interference with the lipid mediator S1P itself has not until recently been emphasized, largely because of difficulties in directly mitigating this lipid target, in particular because of the difficulty first in raising and then in detecting antibodies against the S1P target.
Recently, the generation of antibodies specific for S1P has been described. See, e.g., commonly owned, U.S. patent application Serial No. 20070148168; WO2007/053447. Such antibodies, which can, for example, selectively adsorb S1P from serum, act as molecular sponges to neutralize extracellular S1P. See also commonly owned U.S. Pat. Nos. 6,881,546 and 6,858,383 and U.S. patent application Ser. No. 10/029,372. SPHINGOMAB™, the murine monoclonal antibody (mAb) developed by Lpath, Inc. and described in certain patents or patent applications listed above, has been shown to be effective in models of human disease. In some situations, a humanized antibody may be preferable to a murine antibody, particularly for therapeutic uses in humans, where human-anti-mouse antibody (HAMA) response may occur. Such a response may reduce the effectiveness of the antibody by neutralizing the binding activity and/or by rapidly clearing the antibody from circulation in the body. The HAMA response can also cause toxicities with subsequent administrations of mouse antibodies.
A first-in-class humanized anti-S1P antibody (Sonepcizumab, LT1009) has now been developed and is described herein. This antibody is expected to have all the advantages of the murine mAb in terms of efficacy in binding S1P, neutralizing S1P and modulating disease states related to S1P, but with none of the potential disadvantages of the murine mAb when used in a human context. As described in the examples hereinbelow, this humanized antibody has in fact shown activity greater than that of the parent (murine) antibody in animal models of disease. Sonepcizumab is currently in clinical trials for cancer and age-related macular degeneration.
Lysolipids
Lysolipids are low molecular weight lipids that contain a polar head group and a single hydrocarbon backbone, due to the absence of an acyl group at one or both possible positions of acylation. Relative to the polar head group at sn-3, the hydrocarbon chain can be at the sn-2 and/or sn-1 position(s) (the term “lyso,” which originally related to hemolysis, has been redefined by IUPAC to refer to deacylation). See “Nomenclature of Lipids, www.chem.qmul.ac.uk/iupac/lipid/lip 1n2.html. These lipids are representative of signaling, bioactive lipids, and their biologic and medical importance highlight what can be achieved by targeting lipid signaling molecules for therapeutic, diagnostic/prognostic, or research purposes (Gardell, et al. (2006), Trends in Molecular Medicine, vol 12: 65-75). Two particular examples of medically important lysolipids are LPA (glycerol backbone) and S1P (sphingoid backbone). Other lysolipids include sphingosine, lysophosphatidylcholine (LPC), sphingosylphosphorylcholine (lysosphingomyelin), ceramide, ceramide-1-phosphate, sphinganine (dihydrosphingosine), dihydrosphingosine-1-phosphate and N-acetyl-ceramide-1-phosphate. In contrast, the plasmalogens, which contain an O-alkyl (—O—CH2—) or O-alkenyl ether at the C-1 (sn1) and an acyl at C-2, are excluded from the lysolipid genus.
The structures of selected LPAs, S1P, and dihydro S1P are presented below.

LPA is not a single molecular entity but a collection of endogenous structural variants with fatty acids of varied lengths and degrees of saturation (Fujiwara, et al. (2005), J Biol Chem, vol. 280: 35038-35050). The structural backbone of the LPAs is derived from glycerol-based phospholipids such as phosphatidylcholine (PC) or phosphatidic acid (PA). In the case of lysosphingolipids such as S1P, the fatty acid of the ceramide backbone at sn-2 is missing. The structural backbone of S1P, dihydro S1P (DHS1P) and sphingosylphosphorylcholine (SPC) is based on sphingosine, which is derived from sphingomyelin.
LPA and S1P regulate various cellular signaling pathways by binding to the same class of multiple transmembrane domain G protein-coupled (GPCR) receptors (Chun J, Rosen H (2006), Current Pharm Des, vol. 12: 161-171, and Moolenaar, W H (1999), Experimental Cell Research, vol. 253: 230-238). The S1P receptors are designated as S1P1, S1P2, S1P3, S1P4 and S1P5 (formerly EDG-1, EDG-5/AGR16, EDG-3, EDG-6 and EDG-8) and the LPA receptors designated as LPA1, LPA2, LPA3 (formerly, EDG-2, EDG-4, and EDG-7). A fourth LPA receptor of this family has been identified for LPA (LPA4), and other putative receptors for these lysophospholipids have also been reported.
Lysophosphatic Acids (LPA)
LPAs have long been known as precursors of phospholipid biosynthesis in both eukaryotic and prokaryotic cells, but LPAs have emerged only recently as signaling molecules that are rapidly produced and released by activated cells, notably platelets, to influence target cells by acting on specific cell-surface receptor (see, e.g., Moolenaar, et al. (2004), BioEssays, vol. 26: 870-881, and van Leewen et al. (2003), Biochem Soc Trans, vol 31: 1209-1212). Besides being synthesized and processed to more complex phospholipids in the endoplasmic reticulum, LPA can be generated through the hydrolysis of pre-existing phospholipids following cell activation; for example, the sn-2 position is commonly missing a fatty acid residue due to deacylation, leaving only the sn-1 hydroxyl esterified to a fatty acid. Moreover, a key enzyme in the production of LPA, autotoxin (lysoPLD/NPP2), may be the product of an oncogene, as many tumor types up-regulate autotoxin (Brindley, D. (2004), J Cell Biochem, vol. 92: 900-12). The concentrations of LPA in human plasma and serum have been reported, including determinations made using a sensitive and specific LC/MS procedure (Baker, et al. (2001), Anal Biochem, vol 292: 287-295). For example, in freshly prepared human serum allowed to sit at 25° C. for one hour, LPA concentrations have been estimated to be approximately 1.2 μM, with the LPA analogs 16:0, 18:1, 18:2, and 20:4 being the predominant species. Similarly, in freshly prepared human plasma allowed to sit at 25° C. for one hour, LPA concentrations have been estimated to be approximately 0.7 μM, with 18:1 and 18:2 LPA being the predominant species.
LPA influences a wide range of biological responses, ranging from induction of cell proliferation, stimulation of cell migration and neurite retraction, gap junction closure, and even slime mold chemotaxis (Goetzl, et al. (2002), Scientific World Journal, vol. 2: 324-338). The body of knowledge about the biology of LPA continues to grow as more and more cellular systems are tested for LPA responsiveness. For instance, it is now known that, in addition to stimulating cell growth and proliferation, LPA promote cellular tension and cell-surface fibronectin binding, which are important events in wound repair and regeneration (Moolenaar, et al. (2004), BioEssays, vol. 26: 870-881). Recently, anti-apoptotic activity has also been ascribed to LPA, and it has recently been reported that peroxisome proliferation receptor gamma is a receptor/target for LPA (Simon, et al. (2005), J Biol Chem, vol. 280: 14656-14662). LPA is now recognized as a key signaling molecule involved in the etiology of cancer. Murph, M and Mills, G B (2007) Expert Rev. Mol. Med. 9:1-18.
LPA has proven to be a difficult target for antibody production, although there has been a report in the scientific literature of the production of polyclonal murine antibodies against LPA (Chen et al. (2000) Med Chem Lett, vol 10: 1691-3).
Lpath has recently humanized a monoclonal antibody against LPA, disclosed in US Patent application US20080145360. The humanized anti-LPA antibody, LT3015, exhibits picomolar binding affinity as demonstrated using surface plasmon resonance and is highly specific for LPA.
Structure and Design of Monoclonal Antibodies
Soluble antibodies of the Immunoglobin G (IgG) class consist of a pair of heavy and light chains that are held together by intra- and interchain disulfide bonds to generate the characteristic Y-shaped structure (FIG. 1). In terms of protein tertiary structure, antibodies consist entirely of the immunoglobin domain—a fold that is common to many effector molecules of the immune system. Heavy chains begin with one variable domain (Vh) followed by three constant domains (Ch1-3) while kappa light chains consist of one variable domain (Vk) followed by one constant domain (Ck). Epitope binding specificity results from variability within the amino-terminal Vh and Vk domains, particularly within six loops (CDR H1, H2, H3, L1, L2 and L3) also known as hypervariable regions.
Treatment of purified whole IgG preparations with the protease papain separates a Fab fragment consisting of both variable domains and the Ck and constant domains from the Fc domain, which contains a pair of Ch2 and Ch3 domains. The Fab fragment retains one entire variable region and, therefore, serves as a useful tool for biochemical characterization of a 1:1 interaction between the antibody and epitope. Furthermore, because it lacks the flexibility and, generally, the glycosylation inherent in native purified whole IgG, the Fab fragment is generally an excellent platform for structural studies via single crystal x-ray diffraction.
Currently, there are over 20 therapeutic antibodies on the market. It is the fastest growing segment of therapeutics largely because humanized mAbs have a high safety profile. The huge success of antibody molecular sponges like Avastin, Lucentis, Humira and Remicade have demonstrated that the use of antibody therapeutics in this mode can also be effective in the treatment of cancer, AMD, inflammatory and autoimmune disorders by neutralizing the target (in the cited cases, protein growth factors) in the extracellular space and depriving receptors of their ligand.
Lpath's ImmuneY2™ technology allows generation of monoclonal antibodies (mAb) against extracellular lipid signaling mediators. Lpath has developed a first-in-class therapeutic agent, a humanized monoclonal antibody Sonepcizumab™ (LT1009; the names Sonepcizumab and LT1009 are herein used interchangeably), which was derived from the murine form of the antibody, Sphingomab™. Sonepcizumab neutralizes the bioactive lipid signaling mediator, sphingosine-1-phosphate (S1P). S1P contributes to disease in cancer, multiple sclerosis, inflammatory disease and ocular diseases that involve dysregulated angiogenesis. A systemic formulation of Sonepcizumab, ASONEP™, is currently in Phase 1 trials for cancer while an ocular formulation of the same mAb, iSONEP™, is in Phase 1 clinical trials for Age-related Macular Degeneration (AMD). Lpath has also recently developed the humanized mAb Lpathomab™ (LT3015; the names Lpathomab and LT3015 are herein used interchangeably), a mAb against the bioactive lipid mediator, lysophosphatidic acid (LPA). In addition to regulating physiological responses such as cell adhesion, motility, cytoskeletal changes, proliferation, angiogenesis, neurite retraction, and cell survival, LPA has been implicated in the pathogenesis and progression of severe diseases including cancer, fibrosis, neuropathic pain, and inflammatory diseases.
3. Definitions
Before describing the instant invention in detail, several terms used in the context of the present invention will be defined. In addition to these terms, others are defined elsewhere in the specification, as necessary. Unless otherwise expressly defined herein, terms of art used in this specification will have their art-recognized meanings.
The term “antibody” (“Ab”) or “immunoglobulin” (Ig) refers to any form of a peptide, polypeptide derived from, modeled after or encoded by, an immunoglobulin gene, or fragment thereof, that is capable of binding an antigen or epitope. See, e.g., IMMUNOBIOLOGY, Fifth Edition, C. A. Janeway, P. Travers, M., Walport, M. J. Shlomchiked., ed. Garland Publishing (2001). The term “antibody” is used herein in the broadest sense, and encompasses monoclonal, polyclonal or multispecific antibodies, minibodies, heteroconjugates, diabodies, triabodies, chimeric, antibodies, synthetic antibodies, antibody fragments, and binding agents that employ the complementarity determining regions (CDRs) of the parent antibody, or variants thereof that retain antigen binding activity. Antibodies are defined herein as retaining at least one desired activity of the parent antibody. Desired activities can include the ability to bind the antigen specifically, the ability to inhibit proleration in vitro, the ability to inhibit angiogenesis in vivo, and the ability to alter cytokine profile(s) in vitro.
Native antibodies (native immunoglobulins) are usually heterotetrameric glycoproteins of about 150,000 Daltons, typically composed of two identical light (L) chains and two identical heavy (H) chains. The heavy chain is approximately 50 kD in size, and the light chain is approximately 25 kDa. Each light chain is typically linked to a heavy chain by one covalent disulfide bond, while the number of disulfide linkages varies among the heavy chains of different immunoglobulin isotypes. Each heavy and light chain also has regularly spaced intrachain disulfide bridges. Each heavy chain has at one end a variable domain (VH) followed by a number of constant domains. Each light chain has a variable domain at one end (VL) and a constant domain at its other end; the constant domain of the light chain is aligned with the first constant domain of the heavy chain, and the light-chain variable domain is aligned with the variable domain of the heavy chain. Particular amino acid residues are believed to form an interface between the light- and heavy-chain variable domains.
The light chains of antibodies (immunoglobulins) from any vertebrate species can be assigned to one of two clearly distinct types, called kappa (κ) and lambda (λ), based on the amino acid sequences of their constant domains. The ratio of the two types of light chain varies from species to species. As a way of example, the average κ to λ ratio is 20:1 in mice, whereas in humans it is 2:1 and in cattle it is 1:20.
Depending on the amino acid sequence of the constant domain of their heavy chains, immunoglobulins can be assigned to different classes. There are five major classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM, and several of these may be further divided into subclasses (isotypes), e.g., IgG1, IgG2, IgG3, IgG4, IgA, and IgA2. The heavy-chain constant domains that correspond to the different classes of immunoglobulins are called alpha, delta, epsilon, gamma, and mu, respectively. The subunit structures and three-dimensional configurations of different classes of immunoglobulins are well known.
An “antibody derivative” is an immune-derived moiety, i.e., a molecule that is derived from an antibody. This includes any antibody (Ab) or immunoglobulin (Ig), and refers to any form of a peptide, polypeptide derived from, modeled after or encoded by, an immunoglobulin gene, or a fragment of such peptide or polypeptide that is capable of binding an antigen or epitope. This comprehends, for example, antibody variants, antibody fragments, chimeric antibodies, humanized antibodies, multivalent antibodies, antibody conjugates and the like, which retain a desired level of binding activity for antigen.
As used herein, “antibody fragment” refers to a portion of an intact antibody that includes the antigen binding site or variable regions of an intact antibody, wherein the portion can be free of the constant heavy chain domains (e.g., CH2, CH3, and CH4) of the Fc region of the intact antibody. Alternatively, portions of the constant heavy chain domains (e.g., CH2, CH3, and CH4) can be included in the “antibody fragment”. Antibody fragments retain antigen-binding and include Fab, Fab′, F(ab′)2, Fd, and Fv fragments; diabodies; triabodies; single-chain antibody molecules (sc-Fv); minibodies, nanobodies, and multispecific antibodies formed from antibody fragments. Papain digestion of antibodies produces two identical antigen-binding fragments, called “Fab” fragments, each with a single antigen-binding site, and a residual “Fc” fragment, whose name reflects its ability to crystallize readily. Pepsin treatment yields an F(ab′)2 fragment that has two antigen-combining sites and is still capable of cross-linking antigen. By way of example, a Fab fragment also contains the constant domain of a light chain and the first constant domain (CH1) of a heavy chain. “Fv” is the minimum antibody fragment that contains a complete antigen-recognition and -binding site. This region consists of a dimer of one heavy chain and one light chain variable domain in tight, non-covalent association. It is in this configuration that the three hypervariable regions of each variable domain interact to define an antigen-binding site on the surface of the VH-VL dimer. Collectively, the six hypervariable regions confer antigen-binding specificity to the antibody. However, even a single variable domain (or half of an Fv comprising only three hypervariable regions specific for an antigen) has the ability to recognize and bind antigen, although at a lower affinity than the entire binding site. “Single-chain Fv” or “sFv” antibody fragments comprise the VH and VL domains of antibody, wherein these domains are present in a single polypeptide chain. Generally, the Fv polypeptide further comprises a polypeptide linker between the VH and VL domains that enables the sFv to form the desired structure for antigen binding. For a review of sFv, see Pluckthun in The Pharmacology of Monoclonal Antibodies, vol. 113, Rosenburg and Moore eds. Springer-Verlag, New York, pp. 269-315 (1994).
The Fab fragment also contains the constant domain of the light chain and the first constant domain (CH1) of the heavy chain. Fab′ fragments differ from Fab fragments by the addition of a few residues at the carboxyl terminus of the heavy chain CH1 domain including one or more cysteine(s) from the antibody hinge region. Fab′-SH is the designation herein for Fab′ in which the cysteine residue(s) of the constant domains bear a free thiol group. F(ab′)2 antibody fragments originally were produced as pairs of Fab′ fragments which have hinge cysteines between them. Other chemical couplings of antibody fragments are also known.
An “antibody variant” refers herein to a molecule which differs in amino acid sequence from the amino acid sequence of a native or parent antibody that is directed to the same antigen by virtue of addition, deletion and/or substitution of one or more amino acid residue(s) in the antibody sequence and which retains at least one desired activity of the parent anti-binding antibody. Desired activities can include the ability to bind the antigen specifically, the ability to inhibit proliferation in vitro, the ability to inhibit angiogenesis in vivo, and the ability to alter cytokine profile in vitro. The amino acid change(s) in an antibody variant may be within a variable region or a constant region of a light chain and/or a heavy chain, including in the Fc region, the Fab region, the CH1 domain, the CH2 domain, the CH3 domain, and the hinge region. In one embodiment, the variant comprises one or more amino acid substitution(s) in one or more hypervariable region(s) of the parent antibody. For example, the variant may comprise at least one, e.g. from about one to about ten, and preferably from about two to about five, substitutions in one or more hypervariable regions of the parent antibody. Ordinarily, the variant will have an amino acid sequence having at least 50% amino acid sequence identity with the parent antibody heavy or light chain variable domain sequences, more preferably at least 65%, more preferably at 80%, more preferably at least 85%, more preferably at least 90%, and most preferably at least 95%. Identity or homology with respect to this sequence is defined herein as the percentage of amino acid residues in the candidate sequence that are identical with the parent antibody residues, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity. None of N-terminal, C-terminal, or internal extensions, deletions, or insertions into the antibody sequence shall be construed as affecting sequence identity or homology. The variant retains the ability to bind LPA and preferably has desired activities which are superior to those of the parent antibody. For example, the variant may have a stronger binding affinity, enhanced ability to reduce angiogenesis and/or halt tumor progression. To analyze such desired properties (for example les immunogenic, longer half-life, enhanced stability, enhanced potency), one should compare a Fab form of the variant to a Fab form of the parent antibody or a full length form of the variant to a full length form of the parent antibody, for example, since it has been found that the format of the anti-sphingolipid antibody impacts its activity in the biological activity assays disclosed herein. The variant antibody of particular interest herein can be one which displays at least about 10 fold, preferably at least about % 5, 25, 59, or more of at least one desired activity. The preferred variant is one that has superior biophysical properties as measured in vitro or superior activities biological as measured in vitro or in vivo when compared to the parent antibody.
An “anti-LPA agent” refers to any therapeutic agent that binds LPA, and includes antibodies, antibody variants, antibody-derived molecules or non-antibody-derived moieties that bind LPA and its variants.
An “anti-LPA antibody” or an “immune-derived moiety reactive against LPA” refers to any antibody or antibody-derived molecule that binds LPA. As will be understood from these definitions, antibodies or immune-derived moieties may be polyclonal or monoclonal and may be generated through a variety of means, and/or may be isolated from an animal, including a human subject.
An “anti-S1P agent” refers to any therapeutic agent that binds S1P, and includes antibodies, antibody variants, antibody-derived molecules or non-antibody-derived moieties that bind LPA and its variants.
An “anti-S1P antibody” or an “immune-derived moiety reactive against S1P” refers to any antibody or antibody-derived molecule that binds S1P. As will be understood from these definitions, antibodies or immune-derived moieties may be polyclonal or monoclonal and may be generated through a variety of means, and/or may be isolated from an animal, including a human subject.
A “bioactive lipid” refers to a lipid signaling molecule. Bioactive lipids are distinguished from structural lipids (e.g., membrane-bound phospholipids) in that they mediate extracellular and/or intracellular signaling and thus are involved in controlling the function of many types of cells by modulating differentiation, migration, proliferation, secretion, survival, and other processes. In vivo, bioactive lipids can be found in extracellular fluids, where they can be complexed with other molecules, for example serum proteins such as albumin and lipoproteins, or in “free” form, i.e., not complexed with another molecule species. As extracellular mediators, some bioactive lipids alter cell signaling by activating membrane-bound ion channels or GPCRs or enzymes or factors that, in turn, activate complex signaling systems that result in changes in cell function or survival. As intracellular mediators, bioactive lipids can exert their actions by directly interacting with intracellular components such as enzymes, ion channels or structural elements such as actin.
Examples of bioactive lipids include sphingolipids such as ceramide, ceramide-1-phosphate (C1P), sphingosine, sphinganine, sphingosylphosphorylcholine (SPC) and sphingosine-1-phosphate (S1P). Sphingolipids and their derivatives and metabolites are characterized by a sphingoid backbone (derived from sphingomyelin). Sphingolipids and their derivatives and metabolites represent a group of extracellular and intracellular signaling molecules with pleiotropic effects on important cellular processes. They include sulfatides, gangliosides and cerebrosides. Other bioactive lipids are characterized by a glycerol-based backbone; for example, lysophospholipids such as lysophosphatidyl choline (LPC) and various lysophosphatidic acids (LPA), as well as phosphatidylinositol (PI), phosphatidylethanolamine (PEA), phosphatidic acid, platelet activating factor (PAF), cardiolipin, phosphatidylglycerol (PG) and diacylglyceride (DG). Yet other bioactive lipids are derived from arachidonic acid; these include the eicosanoids (including the eicosanoid metabolites such as the HETEs, cannabinoids, leukotrienes, prostaglandins, lipoxins, epoxyeicosatrienoic acids, and isoeicosanoids), non-eicosanoid cannabinoid mediators. Other bioactive lipids, including other phospholipids and their derivatives, may also be used according to the instant invention.
In some embodiments of the invention it may be preferable to target glycerol-based bioactive lipids (those having a glycerol-derived backbone, such as the LPAs) for antibody production, as opposed to sphingosine-based bioactive lipids (those having a sphingoid backbone, such as sphingosine and S1P). In other embodiments it may be desired to target arachidonic acid-derived bioactive lipids for antibody generation, and in other embodiments arachidonic acid-derived and glycerol-derived bioactive lipids but not sphingoid-derived bioactive lipids are preferred. Together the arachidonic acid-derived and glycerol-derived bioactive lipids may be referred to in the context of this invention as “non-sphingoid bioactive lipids.”
Specifically excluded from the class of bioactive lipids according to the invention are phosphatidylcholine and phosphatidylserine, as well as their metabolites and derivatives that function primarily as structural members of the inner and/or outer leaflet of cellular membranes.
The term “biologically active,” in the context of an antibody or antibody fragment or variant, refers to an antibody or antibody fragment or antibody variant that is capable of binding the desired epitope and in some ways exerting a biologic effect. Biological effects include, but are not limited to, the modulation of a growth signal, the modulation of an anti-apoptotic signal, the modulation of an apoptotic signal, the modulation of the effector function cascade, and modulation of other ligand interactions.
A “biomarker” is a specific biochemical in the body which has a particular molecular feature that makes it useful for measuring the progress of disease or the effects of treatment. For example, S1P is a biomarker for certain hyperproliferative and/or cardiovascular conditions.
The term “cardiotherapeutic agent” refers to an agent that is therapeutic to diseases and diseases caused by or associated with cardiac and myocardial diseases and disorders.
“Cardiovascular therapy” encompasses cardiac therapy (treatment of myocardial ischemia and/or heart failure) as well as the prevention and/or treatment of other diseases associated with the cardiovascular system, such as heart disease. The term “heart disease” encompasses any type of disease, disorder, trauma or surgical treatment that involves the heart or myocardial tissue. Of particular interest are conditions associated with tissue remodeling. The term “cardiotherapeutic agent” refers to an agent that is therapeutic to diseases and diseases caused by or associated with cardiac and myocardial diseases and disorders.
A “carrier” refers to a moiety adapted for conjugation to a hapten, thereby rendering the hapten immunogenic. A representative, non-limiting class of carriers is proteins, examples of which include albumin, keyhole limpet hemocyanin, hemaglutanin, tetanus, and diptheria toxoid. Other classes and examples of carriers suitable for use in accordance with the invention are known in the art. These, as well as later discovered or invented naturally occurring or synthetic carriers, can be adapted for application in accordance with the invention.
As used herein, the expressions “cell,” “cell line,” and “cell culture” are used interchangeably and all such designations include progeny. Thus, the words “transformants” and “transformed cells” include the primary subject cell and cultures derived there from without regard for the number of transfers. It is also understood that all progeny may not be precisely identical in DNA content, due to deliberate or inadvertent mutations. Mutant progeny that have the same function or biological activity as screened for in the originally transformed cell are included. Where distinct designations are intended, it will be clear from the context.
“Cerebrovascular therapy” refers to therapy directed to the prevention and/or treatment of diseases and disorders associated with cerebral ischemia and/or hypoxia. Of particular interest is cerebral ischemia and/or hypoxia resulting from global ischemia resulting from a heart disease, including without limitation heart failure.
The term “chemotherapeutic agent” means anti-cancer and other anti-hyperproliferative agents. Thus chemotherapeutic agents are a subset of therapeutic agents in general. Chemotherapeutic agents include, but are not limited to: DNA damaging agents and agents that inhibit DNA synthesis: anthracyclines (doxorubicin, donorubicin, epirubicin), alkylating agents (bendamustine, busulfan, carboplatin, carmustine, chlorambucil, cyclophosphamide, dacarbazine, hexamethylmelamine, ifosphamide, lomustine, mechlorethamine, melphalan, mitotane, mytomycin, pipobroman, procarbazine, streptozocin, thiotepa, and triethylenemelamine), platinum derivatives (cisplatin, carboplatin, cis diammine-dichloroplatinum), and topoisomerase inhibitors (Camptosar); anti-metabolites such as capecitabine, chlorodeoxyadenosine, cytarabine (and its activated form, ara-CMP), cytosine arabinoside, dacabazine, floxuridine, fludarabine, 5-fluorouracil, 5-DFUR, gemcitabine, hydroxyurea, 6-mercaptopurine, methotrexate, pentostatin, trimetrexate, 6-thioguanine); anti-angiogenics (bevacizumab, thalidomide, sunitinib, lenalidomide, TNP-470, 2-methoxyestradiol, ranibizumab, sorafenib, erlotinib, bortezomib, pegaptanib, endostatin); vascular disrupting agents (flavonoids/flavones, DMXAA, combretastatin derivatives such as CA4DP, ZD6126, AVE8062A, etc.); biologics such as antibodies (Herceptin, Avastin, Panorex, Rituxin, Zevalin, Mylotarg, Campath, Bexxar, Erbitux); endocrine therapy: aromatase inhibitors (4-hydroandrostendione, exemestane, aminoglutehimide, anastrazole, letozole), anti-estrogens (Tamoxifen, Toremifine, Raoxifene, Faslodex), steroids such as dexamethasone; immuno-modulators: cytokines such as IFN-beta and IL2), inhibitors to integrins, other adhesion proteins and matrix metalloproteinases); histone deacetylase inhibitors like suberoylanilide hydroxamic acid; inhibitors of signal transduction such as inhibitors of tyrosine kinases like imatinib (Gleevec); inhibitors of heat shock proteins like 17-N-allylamino-17-demethoxygeldanamycin; retinoids such as all trans retinoic acid; inhibitors of growth factor receptors or the growth factors themselves; anti-mitotic compounds and/or tubulin-depolymerizing agents such as the taxoids (paclitaxel, docetaxel, taxotere, BAY 59-8862), navelbine, vinblastine, vincristine, vindesine and vinorelbine; anti-inflammatories such as COX inhibitors and cell cycle regulators, e.g., check point regulators and telomerase inhibitors.
The term “chimeric” antibody (or immunoglobulin) refers to a molecule comprising a heavy and/or light chain which is identical with or homologous to corresponding sequences in antibodies derived from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chain(s) is identical with or homologous to corresponding sequences in antibodies derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, so long as they exhibit the desired biological activity (Cabilly, et al., infra; Morrison et al., Proc. Natl. Acad. Sci. U.S.A., vol. 81:6851 (1984)).
The term “combination therapy” refers to a therapeutic regimen that involves the provision of at least two distinct therapies to achieve an indicated therapeutic effect. For example, a combination therapy may involve the administration of two or more chemically distinct active ingredients, for example, a fast-acting chemotherapeutic agent and an anti-lipid antibody, or two different antibodies. Alternatively, a combination therapy may involve the administration of an anti-lipid antibody together with the delivery of another treatment, such as radiation therapy and/or surgery. Further, a combination therapy may involve administration of an anti-lipid antibody together with one or more other biological agents (e.g., anti-VEGF, TGFβ, PDGF, or bFGF agent), chemotherapeutic agents and another treatment such as radiation and/or surgery. In the context of the administration of two or more chemically distinct active ingredients, it is understood that the active ingredients may be administered as part of the same composition or as different compositions. When administered as separate compositions, the compositions comprising the different active ingredients may be administered at the same or different times, by the same or different routes, using the same of different dosing regimens, all as the particular context requires and as determined by the attending physician. Similarly, when one or more anti-lipid antibody species, for example, an anti-LPA antibody, alone or in conjunction with one or more chemotherapeutic agents are combined with, for example, radiation and/or surgery, the drug(s) may be delivered before or after surgery or radiation treatment.
The term “constant domain” refers to the C-terminal region of an antibody heavy or light chain. Generally, the constant domains are not directly involved in the binding properties of an antibody molecule to an antigen, but exhibit various effector functions, such as participation of the antibody in antibody-dependent cellular toxicity. Here, “effector functions” refer to the different physiological effects of antibodies (e.g., opsonization, cell lysis, mast cell, basophil and eosinophil degranulation, and other processes) mediated by the recruitment of immune cells by the molecular interaction between the Fc domain and proteins of the immune system. The isotype of the heavy chain determines the functional properties of the antibody. Their distinctive functional properties are conferred by the carboxy-terminal portions of the heavy chains, where they are not associated with light chains.
The expression “control sequences” refers to DNA sequences necessary for the expression of an operably linked coding sequence in a particular host organism. The control sequences that are suitable for prokaryotes, for example, include a promoter, optionally an operator sequence, and a ribosome binding site. Eukaryotic cells are known to utilize promoters, polyadenylation signals, and enhancers.
A “derivatized bioactive lipid” is a bioactive lipid, e.g., LPA, which has a polar head group and at least one hydrocarbon chain, wherein a carbon atom within the hydrocarbon chain is derivatized with a pendant reactive group [e.g., a sulfhydryl (thiol) group, a carboxylic acid group, a cyano group, an ester, a hydroxy group, an alkene, an alkyne, an acid chloride group or a halogen atom] that may or may not be protected. This derivatization serves to activate the bioactive lipid for reaction with a molecule, e.g., for conjugation to a carrier.
A “derivatized bioactive lipid conjugate” refers to a derivatized bioactive lipid that is covalently conjugated to a carrier. The carrier may be a protein molecule or may be a moiety such as polyethylene glycol, colloidal gold, adjuvants or silicone beads. A derivatized bioactive lipid conjugate may be used as an immunogen for generating an antibody response according to the instant invention, and the same or a different bioactive lipid conjugate may be used as a detection reagent for detecting the antibody thus produced. In some embodiments the derivatized bioactive lipid conjugate is attached to a solid support when used for detection.
The term “diabodies” refers to small antibody fragments with two antigen-binding sites, which fragments comprise a heavy chain variable domain (VH) connected to a light chain variable domain (VL) in the same polypeptide chain (VH-VL). By using a linker that is too short to allow pairing between the two domains on the same chain, the domains are forced to pair with the complementary domains of another chain and create two antigen-binding sites. Diabodies are described more fully in, for example, EP 404,097; WO 93/11161; and Hollinger et al., Proc. Natl. Acad. Sci. USA 90:6444-6448 (1993).
“Effective concentration” refers to the absolute, relative, and/or available concentration and/or activity, for example of certain undesired bioactive lipids. In other words, the effective concentration of a bioactive lipid is the amount of lipid available, and able, to perform its biological function. In the present invention, an immune-derived moiety such as, for example, a monoclonal antibody directed to a bioactive lipid (such as, for example, C1P) is able to reduce the effective concentration of the lipid by binding to the lipid and rendering it unable to perform its biological function. In this example, the lipid itself is still present (it is not degraded by the antibody, in other words) but can no longer bind its receptor or other targets to cause a downstream effect, so “effective concentration” rather than absolute concentration is the appropriate measurement. Methods and assays exist for directly and/or indirectly measuring the effective concentration of bioactive lipids.
An “epitope” or “antigenic determinant” refers to that portion of an antigen that reacts with an antibody antigen-binding portion derived from an antibody.
The term “expression cassette” refers to a nucleotide molecule capable of affecting expression of a structural gene (i.e., a protein coding sequence, such as an antibody of the invention) in a host compatible with such sequences. Expression cassettes include at least a promoter operably linked with the polypeptide-coding sequence, and, optionally, with other sequences, e.g., transcription termination signals. Additional regulatory elements necessary or helpful in effecting expression may also be used, e.g., enhancers. Thus, expression cassettes include plasmids, expression vectors, recombinant viruses, any form of recombinant “naked DNA” vector, and the like.
A “fully human antibody” can refer to an antibody produced in a genetically engineered (i.e., transgenic) mouse (e.g. from Medarex) that, when presented with an immunogen, can produce a human antibody that does not necessarily require CDR grafting. These antibodies are fully human (100% human protein sequences) from animals such as mice in which the non-human antibody genes are suppressed and replaced with human antibody gene expression. The applicants believe that antibodies could be generated against bioactive lipids when presented to these genetically engineered mice or other animals who might be able to produce human frameworks for the relevant CDRs.
A “hapten” is a substance that is non-immunogenic but can react with an antibody or antigen-binding portion derived from an antibody. In other words, haptens have the property of antigenicity but not immunogenicity. A hapten is generally a small molecule that can, under most circumstances, elicit an immune response (i.e., act as an antigen) only when attached to a carrier, for example, a protein, polyethylene glycol (PEG), colloidal gold, silicone beads, or the like. The carrier may be one that also does not elicit an immune response by itself. A representative, non-limiting class of hapten molecules is proteins, examples of which include albumin, keyhole limpet hemocyanin, hemaglutanin, tetanus, and diphtheria toxoid. Other classes and examples of hapten molecules are known in the art. These, as well as later discovered or invented naturally occurring or synthetic haptens, can be adapted for application in accordance with the invention.
The term “heteroconjugate antibody” can refer to two covalently joined antibodies. Such antibodies can be prepared using known methods in synthetic protein chemistry, including using crosslinking agents. As used herein, the term “conjugate” refers to molecules formed by the covalent attachment of one or more antibody fragment(s) or binding moieties to one or more polymer molecule(s).
“Humanized” forms of non-human (e.g., murine) antibodies are chimeric antibodies that contain minimal sequence derived from non-human immunoglobulin. Or, looked at another way, a humanized antibody is a human antibody that also contains selected sequences from non-human (e.g., murine) antibodies in place of the human sequences. A humanized antibody can include conservative amino acid substitutions or non-natural residues from the same or different species that do not significantly alter its binding and/or biologic activity. Such antibodies are chimeric antibodies that contain minimal sequence derived from non-human immunoglobulins. For the most part, humanized antibodies are human immunoglobulins (recipient antibody) in which residues from a complementary-determining region (CDR) of the recipient are replaced by residues from a CDR of a non-human species (donor antibody) such as mouse, rat, camel, bovine, goat, or rabbit having the desired properties. In some instances, framework region (FR) residues of the human immunoglobulin are replaced by corresponding non-human residues.
Furthermore, humanized antibodies can comprise residues that are found neither in the recipient antibody nor in the imported CDR or framework sequences. These modifications are made to further refine and maximize antibody performance. Thus, in general, a humanized antibody will comprise all of at least one, and in one aspect two, variable domains, in which all or all of the hypervariable loops correspond to those of a non-human immunoglobulin and all or substantially all of the FR regions are those of a human immunoglobulin sequence. The humanized antibody optionally also will comprise at least a portion of an immunoglobulin constant region (Fc), or that of a human immunoglobulin. See, e.g., Cabilly, et al., U.S. Pat. No. 4,816,567; Cabilly, et al., European Patent No. 0,125,023 B1; Boss, et al., U.S. Pat. No. 4,816,397; Boss, et al., European Patent No. 0,120,694 B1; Neuberger, et al., WO 86/01533; Neuberger, et al., European Patent No. 0,194,276 B1; Winter, U.S. Pat. No. 5,225,539; Winter, European Patent No. 0,239,400 B1; Padlan, et al., European Patent Application No. 0,519,596 A1; Queen, et al. (1989), Proc. Nat'l Acad. Sci. USA, vol. 86:10029-10033). For further details, see Jones et al., Nature 321:522-525 (1986); Reichmann et al., Nature 332:323-329 (1988); and Presta, Curr. Op. Struct. Biol. 2:593-596 (1992) and Hansen, WO2006105062.
The term “hyperproliferative disorder” refers to diseases and disorders associated with, the uncontrolled proliferation of cells, including but not limited to uncontrolled growth of organ and tissue cells resulting in cancers and benign tumors. Hyperproliferative disorders associated with endothelial cells can result in diseases of angiogenesis such as angiomas, endometriosis, obesity, age-related macular degeneration and various retinopathies, as well as the proliferation of endothelial cells and smooth muscle cells that cause restenosis as a consequence of stenting in the treatment of atherosclerosis. Hyperproliferative disorders involving fibroblasts (i.e., fibrogenesis) include but are not limited to disorders of excessive scarring (i.e., fibrosis) such as age-related macular degeneration, cardiac remodeling and failure associated with myocardial infarction, excessive wound healing such as commonly occurs as a consequence of surgery or injury, keloids, and fibroid tumors and stenting.
An “immune-derived moiety” includes any antibody (Ab) or immunoglobulin (Ig), and refers to any form of a peptide, polypeptide derived from, modeled after or encoded by, an immunoglobulin gene, or a fragment of such peptide or polypeptide that is capable of binding an antigen or epitope (see, e.g., Immunobiology, 5th Edition, Janeway, Travers, Walport, Shlomchiked. (editors), Garland Publishing (2001)). In the present invention, the antigen is a lipid molecule, such as a bioactive lipid molecule.
An “immunogen” is a molecule capable of inducing a specific immune response, particularly an antibody response in an animal to whom the immunogen has been administered. In the instant invention, the immunogen is a derivatized bioactive lipid conjugated to a carrier, i.e., a “derivatized bioactive lipid conjugate”. The derivatized bioactive lipid conjugate used as the immunogen may be used as capture material for detection of the antibody generated in response to the immunogen. Thus the immunogen may also be used as a detection reagent. Alternatively, the derivatized bioactive lipid conjugate used as capture material may have a different linker and/or carrier moiety from that in the immunogen.
The phrase “in silico” refers to computer simulations that model natural or laboratory processes
To “inhibit,” particularly in the context of a biological phenomenon, means to decrease, suppress or delay. For example, a treatment yielding “inhibition of tumorigenesis” may mean that tumors do not form at all, or that they form more slowly, or are fewer in number than in the untreated control.
An “isolated” antibody is one that has been identified and separated and/or recovered from a component of its natural environment. Contaminant components of its natural environment are materials that would interfere with diagnostic or therapeutic uses for the antibody, and may include enzymes, hormones, and other proteinaceous or nonproteinaceous solutes. In preferred embodiments, the antibody will be purified (1) to greater than 95% by weight of antibody as determined by the Lowry method, and most preferably more than 99% by weight, (2) to a degree sufficient to obtain at least 15 residues of N-terminal or internal amino acid sequence by use of a spinning cup sequenator, or (3) to homogeneity by SDS-PAGE under reducing or nonreducing conditions using Coomassie blue or, preferably, silver stain. Isolated antibody includes the antibody in situ within recombinant cells since at least one component of the antibody's natural environment will not be present. Ordinarily, however, isolated antibody will be prepared by at least one purification step.
The word “label” when used herein refers to a detectable compound or composition, such as one that is conjugated directly or indirectly to the antibody. The label may itself be detectable by itself (e.g., radioisotope labels or fluorescent labels) or, in the case of an enzymatic label, may catalyze chemical alteration of a substrate compound or composition that is detectable.
A “ligand” is a substance that is able to bind to and form a complex with a biomolecule to serve a biological purpose. Thus an antigen may be described as a ligand of the antibody to which it binds.
A “liposome” is a small vesicle composed of various types of lipids, phospholipids and/or surfactant that is useful for delivery of a drug (such as the anti-sphingolipid antibodies disclosed herein and, optionally, a chemotherapeutic agent) to a mammal. The components of the liposome are commonly arranged in a bilayer formation, similar to the lipid arrangement of biological membranes. An “isolated” nucleic acid molecule is a nucleic acid molecule that is identified and separated from at least one contaminant nucleic acid molecule with which it is ordinarily associated in the natural source of the antibody nucleic acid. An isolated nucleic acid molecule is other than in the form or setting in which it is found in nature. Isolated nucleic acid molecules therefore are distinguished from the nucleic acid molecule as it exists in natural cells. However, an isolated nucleic acid molecule includes a nucleic acid molecule contained in cells that ordinarily express the antibody where, for example, the nucleic acid molecule is in a chromosomal location different from that of natural cells.
In the context of this invention, a “liquid composition” refers to one that, in its filled and finished form as provided from a manufacturer to an end user (e.g., a doctor or nurse), is a liquid or solution, as opposed to a solid. Here, “solid” refers to compositions that are not liquids or solutions. For example, solids include dried compositions prepared by lyophilization, freeze-drying, precipitation, and similar procedures.
The expression “linear antibodies” when used throughout this application refers to the antibodies described in Zapata et al. Protein Eng. 8(10):1057-1062 (1995). Briefly, these antibodies comprise a pair of tandem Fd segments (VH-CH1-VH-CH1) that form a pair of antigen binding regions. Linear antibodies can be bispecific or monospecific.
The term “metabolites” refers to compounds from which LPAs are made, as well as those that result from the degradation of LPAs; that is, compounds that are involved in the lysophospholipid metabolic pathways. The term “metabolic precursors” may be used to refer to compounds from which sphingolipids are made.
The term “monoclonal antibody” (mAb) as used herein refers to an antibody obtained from a population of substantially homogeneous antibodies, or to said population of antibodies. The individual antibodies comprising the population are essentially identical, except for possible naturally occurring mutations that may be present in minor amounts. Monoclonal antibodies are highly specific, being directed against a single antigenic site. Furthermore, in contrast to conventional (polyclonal) antibody preparations that typically include different antibodies directed against different determinants (epitopes), each monoclonal antibody is directed against a single determinant on the antigen. The modifier “monoclonal” indicates the character of the antibody as being obtained from a substantially homogeneous population of antibodies, and is not to be construed as requiring production of the antibody by any particular method. For example, the monoclonal antibodies to be used in accordance with the present invention may be made by the hybridoma method first described by Kohler et al., Nature 256:495 (1975), or may be made by recombinant DNA methods (see, e.g., U.S. Pat. No. 4,816,567). The “monoclonal antibodies” may also be isolated from phage antibody libraries using the techniques described in Clackson et al., Nature 352:624-628 (1991) and Marks et al., J. Mol. Biol. 222:581-597 (1991), for example, or by other methods known in the art. The monoclonal antibodies herein specifically include chimeric antibodies in which a portion of the heavy and/or light chain is identical with or homologous to corresponding sequences in antibodies derived from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chain(s) is identical with or homologous to corresponding sequences in antibodies derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, so long as they exhibit the desired biological activity (U.S. Pat. No. 4,816,567; and Morrison et al., Proc. Natl. Acad. Sci. USA 81:6851-6855 (1984)).
“Monotherapy” refers to a treatment regimen based on the delivery of one therapeutically effective compound, whether administered as a single dose or several doses over time.
The term “multispecific antibody” can refer to an antibody, or a monoclonal antibody, having binding properties for at least two different epitopes. In one embodiment, the epitopes are from the same antigen. In another embodiment, the epitopes are from two or more different antigens. Methods for making multispecific antibodies are known in the art. Multispecific antibodies include bispecific antibodies (having binding properties for two epitopes), trispecific antibodies (three epitopes) and so on. For example, multispecific antibodies can be produced recombinantly using the co-expression of two or more immunoglobulin heavy chain/light chain pairs. Alternatively, multispecific antibodies can be prepared using chemical linkage. One of skill can produce multispecific antibodies using these or other methods as may be known in the art. Multispecific antibodies include multispecific antibody fragments. One example of a multispecific (in this case, bispecific) antibody comprehended by this invention is an antibody having binding properties for an S1P epitope and a C1P epitope, which thus is able to recognize and bind to both S1P and C1P. Another example of a bispecific antibody comprehended by this invention is an antibody having binding properties for an epitope from a bioactive lipid and an epitope from a cell surface antigen. Thus the antibody is able to recognize and bind the bioactive lipid and is able to recognize and bind to cells, e.g., for targeting purposes.
“Neoplasia” or “cancer” refers to abnormal and uncontrolled cell growth. A “neoplasm”, or tumor or cancer, is an abnormal, unregulated, and disorganized proliferation of cell growth, and is generally referred to as cancer. A neoplasm may be benign or malignant. A neoplasm is malignant, or cancerous, if it has properties of destructive growth, invasiveness, and metastasis. Invasiveness refers to the local spread of a neoplasm by infiltration or destruction of surrounding tissue, typically breaking through the basal laminas that define the boundaries of the tissues, thereby often entering the body's circulatory system. Metastasis typically refers to the dissemination of tumor cells by lymphatics or blood vessels. Metastasis also refers to the migration of tumor cells by direct extension through serous cavities, or subarachnoid or other spaces. Through the process of metastasis, tumor cell migration to other areas of the body establishes neoplasms in areas away from the site of initial appearance.
Nucleic acid is “operably linked” when it is placed into a functional relationship with another nucleic acid sequence. For example, DNA for a presequence or secretory leader is operably linked to DNA for a polypeptide if it is expressed as a preprotein that participates in the secretion of the polypeptide; a promoter or enhancer is operably linked to a coding sequence if it affects the transcription of the sequence; or a ribosome binding site is operably linked to a coding sequence if it is positioned so as to facilitate translation. Generally, “operably linked” means that the DNA sequences being linked are contiguous, and, in the case of a secretory leader, contiguous and in reading phase. However, enhancers do not have to be contiguous. Linking is accomplished by ligation at convenient restriction sites. If such sites do not exist, the synthetic oligonucleotide adaptors or linkers are used in accordance with conventional practice.
The “parent” antibody herein is one that is encoded by an amino acid sequence used for the preparation of the variant. The parent antibody may be a native antibody or may already be a variant, e.g., a chimeric antibody. For example, the parent antibody may be a humanized or human antibody.
A “patentable” composition, process, machine, or article of manufacture according to the invention means that the subject matter satisfies all statutory requirements for patentability at the time the analysis is performed. For example, with regard to novelty, non-obviousness, or the like, if later investigation reveals that one or more claims encompass one or more embodiments that would negate novelty, non-obviousness, etc., the claim(s), being limited by definition to “patentable” embodiments, specifically exclude the non-patentable embodiment(s). Also, the claims appended hereto are to be interpreted both to provide the broadest reasonable scope, as well as to preserve their validity. Furthermore, the claims are to be interpreted in a way that (1) preserves their validity and (2) provides the broadest reasonable interpretation under the circumstances, if one or more of the statutory requirements for patentability are amended or if the standards change for assessing whether a particular statutory requirement for patentability is satisfied from the time this application is filed or issues as a patent to a time the validity of one or more of the appended claims is questioned.
The term “pharmaceutically acceptable salt” refers to a salt, such as used in formulation, which retains the biological effectiveness and properties of the agents and compounds of this invention and which are is biologically or otherwise undesirable. In many cases, the agents and compounds of this invention are capable of forming acid and/or base salts by virtue of the presence of charged groups, for example, charged amino and/or carboxyl groups or groups similar thereto. Pharmaceutically acceptable acid addition salts may be prepared from inorganic and organic acids, while pharmaceutically acceptable base addition salts can be prepared from inorganic and organic bases. For a review of pharmaceutically acceptable salts (see Berge, et al. (1977) J. Pharm. Sci., vol. 66, 1-19).
A “plurality” means more than one.
The term “promoter” includes all sequences capable of driving transcription of a coding sequence in a cell. Thus, promoters used in the constructs of the invention include cis-acting transcriptional control elements and regulatory sequences that are involved in regulating or modulating the timing and/or rate of transcription of a gene. For example, a promoter can be a cis-acting transcriptional control element, including an enhancer, a promoter, a transcription terminator, an origin of replication, a chromosomal integration sequence, 5′ and 3′ untranslated regions, or an intronic sequence, which are involved in transcriptional regulation. Transcriptional regulatory regions suitable for use in the present invention include but are not limited to the human cytomegalovirus (CMV) immediate-early enhancer/promoter, the SV40 early enhancer/promoter, the E. coli lac or trp promoters, and other promoters known to control expression of genes in prokaryotic or eukaryotic cells or their viruses.
The term “recombinant DNA” refers to nucleic acids and gene products expressed therefrom that have been engineered, created, or modified by man. “Recombinant” polypeptides or proteins are polypeptides or proteins produced by recombinant DNA techniques, for example, from cells transformed by an exogenous DNA construct encoding the desired polypeptide or protein. “Synthetic” polypeptides or proteins are those prepared by chemical synthesis.
The terms “separated”, “purified”, “isolated”, and the like mean that one or more components of a sample contained in a sample-holding vessel are or have been physically removed from, or diluted in the presence of, one or more other sample components present in the vessel. Sample components that may be removed or diluted during a separating or purifying step include, chemical reaction products, non-reacted chemicals, proteins, carbohydrates, lipids, and unbound molecules.
By “solid phase” is meant a non-aqueous matrix such as one to which the antibody of the present invention can adhere. Examples of solid phases encompassed herein include those formed partially or entirely of glass (e.g. controlled pore glass), polysaccharides (e.g., agarose), polyacrylamides, polystyrene, polyvinyl alcohol and silicones. In certain embodiments, depending on the context, the solid phase can comprise the well of an assay plate; in others it is a purification column (e.g. an affinity chromatography column). This term also includes a discontinuous solid phase of discrete particles, such as those described in U.S. Pat. No. 4,275,149.
The term “species” is used herein in various contexts, e.g., a particular species of chemotherapeutic agent. In each context, the term refers to a population of chemically indistinct molecules of the sort referred in the particular context.
The term “specific” or “specificity” in the context of antibody-antigen interactions refers to the selective, non-random interaction between an antibody and its target epitope. Here, the term “antigen” refers to a molecule that is recognized and bound by an antibody molecule or other immune-derived moiety. The specific portion of an antigen that is bound by an antibody is termed the “epitope”. This interaction depends on the presence of structural, hydrophobic/hydrophilic, and/or electrostatic features that allow appropriate chemical or molecular interactions between the molecules. Thus an antibody is commonly said to “bind” (or “specifically bind”) or be “reactive with” (or “specifically reactive with), or, equivalently, “reactive against” (or “specifically reactive against”) the epitope of its target antigen. Antibodies are commonly described in the art as being “against” or “to” their antigens as shorthand for antibody binding to the antigen. Thus an “antibody that binds C1P,” an “antibody reactive against C1P,” an “antibody reactive with C1P,” an “antibody to C1P” and an “anti-C1P antibody” all have the same meaning in the art. Antibody molecules can be tested for specificity of binding by comparing binding to the desired antigen to binding to unrelated antigen or analogue antigen or antigen mixture under a given set of conditions. Preferably, an antibody according to the invention will lack significant binding to unrelated antigens, or even analogs of the target antigen. “Specifically associate” and “specific association” and the like refer to a specific, non-random interaction between two molecules, which interaction depends on the presence of structural, hydrophobic/hydrophilic, and/or electrostatic features that allow appropriate chemical or molecular interactions between the molecules.
The term “sphingolipid” as used herein refers to the class of compounds in the art known as sphingolipids, including, but not limited to the following compounds (see http//www.lipidmaps.org for chemical formulas, structural information, etc. for the corresponding compounds):
Sphingoid bases [SP01]
Sphing-4-enines (Sphingosines) [SP0101]
Sphinganines [SP0102]
4-Hydroxysphinganines (Phytosphingosines) [SP0103]
Sphingoid base homologs and variants [SP0104]
Sphingoid base 1-phosphates [SP0105]
Lysosphingomyelins and lysoglycosphingolipids [SP0106]
N-methylated sphingoid bases [SP0107]
Sphingoid base analogs [SP0108]
Ceramides [SP02]
N-acylsphingosines (ceramides) [SP0201]
N-acylsphinganines (dihydroceramides) [SP0202]
N-acyl-4-hydroxysphinganines (phytoceramides) [SP0203]
Acylceramides [SP0204]
Ceramide 1-phosphates [SP0205]
Phosphosphingolipids [SP03]
Ceramide phosphocholines (sphingomyelins) [SP0301]
Ceramide phosphoethanolamines [SP0302]
Ceramide phosphoinositols [SP0303]
Phosphonosphingolipids [SP04]
Neutral glycosphingolipids [SP05]
Simple Glc series (GlcCer, LacCer, etc) [SP0501]
GalNAcb1-3Gala1-4Galb1-4Glc- (Globo series) [SP0502]
GalNAcb1-4Galb1-4Glc- (Ganglio series) [SP0503]
Galb1-3GlcNAcb1-3Galb1-4Glc- (Lacto series) [SP0504]
Galb1-4GlcNAcb1-3Galb1-4Glc- (Neolacto series) [SP0505]
GalNAcb1-3Gala1-3Galb1-4Glc- (Isoglobo series) [SP0506]
GlcNAcb1-2Mana1-3Manb1-4Glc- (Mollu series) [SP0507]
GalNAcb1-4GlcNAcb1-3Manb1-4Glc- (Arthro series) [SP0508]
Gal- (Gala series) [SP0509]
Other [SP0510]
Acidic glycosphingolipids [SP06]
Gangliosides [SP0601]
Sulfoglycosphingolipids (sulfatides) [SP0602]
Glucuronosphingolipids [SP0603]
Phosphoglycosphingolipids [SP0604]
Other [SP0600]
Basic glycosphingolipids [SP07]
Amphoteric glycosphingolipids [SP08]
Arsenosphingolipids [SP09]
The present invention relates to anti-lipid agents, including anti-sphingolipid antibodies, that are useful for treating or preventing hyperproliferative disorders such as cancer and cardiovascular or cerebrovascular diseases and disorders and various ocular disorders, as described in greater detail below. The invention relates, among others, to antibodies to S1P and its variants including but are not limited to sphingosine-1-phosphate [sphingene-1-phosphate; D-erythro-sphingosine-1-phosphate; sphing-4-enine-1-phosphate; (E,2S,3R)-2-amino-3-hydroxy-octadec-4-enoxy]phosphonic acid (AS 26993-30-6), DHS1P is defined as dihydrosphingosine-1-phosphate [sphinganine-1-phosphate; [(2S,3R)-2-amino-3-hydroxy-octadecoxy]phosphonic acid; D-Erythro-dihydro-D-sphingosine-1-phosphate (CAS19794-97-9]; SPC is sphingosylphosphoryl choline, lysosphingomyelin, sphingosylphosphocholine, sphingosine phosphorylcholine, ethanaminium; 2-((((2-amino-3-hydroxy-4-octadecenyl)oxy)hydroxyphosphinyl)oxy)-N,N,N-trimethyl-, chloride, (R—(R*,S*-(E))), 2-[[(E,2R,3S)-2-amino-3-hydroxy-octadec-4-enoxy]-hydroxy-phosphoryl]oxyethyl1-trimethyl-azanium chloride (CAS 10216-23-6).
The term “sphingolipid metabolite” refers to a compound from which a sphingolipid is made, as well as a that results from the degradation of a particular sphingolipid. In other words, a “sphingolipid metabolite” is a compound that is involved in the sphingolipid metabolic pathways. Metabolites include metabolic precursors and metabolic products. The term “metabolic precursors” refers to compounds from which sphingolipids are made. Metabolic precursors of particular interest include but are not limited to SPC, sphingomyelin, dihydrosphingosine, dihydroceramide, and 3-ketosphinganine. The term “metabolic products” refers to compounds that result from the degradation of sphingolipids, such as phosphorylcholine (e.g., phosphocholine, choline phosphate), fatty acids, including free fatty acids, and hexadecanal (e.g., palmitaldehyde).
Herein, “stable” refers to an interaction between two molecules (e.g., a peptide and a TLR molecule) that is sufficiently stable such that the molecules can be maintained for the desired purpose or manipulation. For example, a “stable” interaction between a peptide and a TLR molecule refers to one wherein the peptide becomes and remains associated with a TLR molecule for a period sufficient to achieve the desired effect.
A “subject” or “patient” refers to an animal in need of treatment that can be effected by molecules of the invention Animals that can be treated in accordance with the invention include vertebrates, with mammals such as bovine, canine, equine, feline, ovine, porcine, and primate (including humans and non-human primates) animals being particularly preferred examples.
A “surrogate marker” refers to laboratory measurement of biological activity within the body that indirectly indicates the effect of treatment on disease state. Examples of surrogate markers for hyperproliferative and/or cardiovascular conditions include SPHK and/or S1PRs.
A “therapeutic agent” refers to a drug or compound that is intended to provide a therapeutic effect including, but not limited to: anti-inflammatory drugs including COX inhibitors and other NSAIDS, anti-angiogenic drugs, chemotherapeutic drugs as defined above, cardiovascular agents, immunomodulatory agents, agents that are used to treat neurodegenerative disorders, opthalmic drugs, anti-fibrotics, etc.
A “therapeutically effective amount” (or “effective amount”) refers to an amount of an active ingredient, e.g., an agent according to the invention, sufficient to effect treatment when administered to a subject in need of such treatment. Accordingly, what constitutes a therapeutically effective amount of a composition according to the invention may be readily determined by one of ordinary skill in the art. In the context of cancer therapy, a “therapeutically effective amount” is one that produces an objectively measured change in one or more parameters associated with cancer cell survival or metabolism, including an increase or decrease in the expression of one or more genes correlated with the particular cancer, reduction in tumor burden, cancer cell lysis, the detection of one or more cancer cell death markers in a biological sample (e.g., a biopsy and an aliquot of a bodily fluid such as whole blood, plasma, serum, urine, etc.), induction of induction apoptosis or other cell death pathways, etc. Of course, the therapeutically effective amount will vary depending upon the particular subject and condition being treated, the weight and age of the subject, the severity of the disease condition, the particular compound chosen, the dosing regimen to be followed, timing of administration, the manner of administration and the like, all of which can readily be determined by one of ordinary skill in the art. It will be appreciated that in the context of combination therapy, what constitutes a therapeutically effective amount of a particular active ingredient may differ from what constitutes a therapeutically effective amount of the active ingredient when administered as a monotherapy (i.e., a therapeutic regimen that employs only one chemical entity as the active ingredient).
The compositions of the invention are used in methods of bioactive lipid-based therapy. As used herein, the terms “therapy” and “therapeutic” encompasses the full spectrum of prevention and/or treatments for a disease, disorder or physical trauma. A “therapeutic” agent of the invention may act in a manner that is prophylactic or preventive, including those that incorporate procedures designed to target individuals that can be identified as being at risk (pharmacogenetics); or in a manner that is ameliorative or curative in nature; or may act to slow the rate or extent of the progression of at least one symptom of a disease or disorder being treated; or may act to minimize the time required, the occurrence or extent of any discomfort or pain, or physical limitations associated with recuperation from a disease, disorder or physical trauma; or may be used as an adjuvant to other therapies and treatments.
The term “treatment” or “treating” means any treatment of a disease or disorder, including preventing or protecting against the disease or disorder (that is, causing the clinical symptoms not to develop); inhibiting the disease or disorder (i.e., arresting, delaying or suppressing the development of clinical symptoms; and/or relieving the disease or disorder (i.e., causing the regression of clinical symptoms). As will be appreciated, it is not always possible to distinguish between “preventing” and “suppressing” a disease or disorder because the ultimate inductive event or events may be unknown or latent. Those “in need of treatment” include those already with the disorder as well as those in which the disorder is to be prevented. Accordingly, the term “prophylaxis” will be understood to constitute a type of “treatment” that encompasses both “preventing” and “suppressing”. The term “protection” thus includes “prophylaxis”.
The term “therapeutic regimen” means any treatment of a disease or disorder using chemotherapeutic and cytotoxic agents, radiation therapy, surgery, gene therapy, DNA vaccines and therapy, siRNA therapy, anti-angiogenic therapy, immunotherapy, bone marrow transplants, aptamers and other biologics such as antibodies and antibody variants, receptor decoys and other protein-based therapeutics.
The “variable” region of an antibody comprises framework and complementarity determining regions (CDRs, otherwise known as hypervariable regions). The variability is not evenly distributed throughout the variable domains of antibodies. It is concentrated in six CDR segments, three in each of the light chain and the heavy chain variable domains. The more highly conserved portions of variable domains are called the framework region (FR). The variable domains of native heavy and light chains each comprise four FRs (FR1, FR2, FR3 and FR4, respectively), largely adopting β-sheet configuration, connected by three hypervariable regions, which form loops connecting, and in some cases forming part of, the beta-sheet structure. The term “hypervariable region” when used herein refers to the amino acid residues of an antibody which are responsible for antigen binding. The hypervariable region comprises amino acid residues from a “complementarity determining region” or “CDR” (for example residues 24-34 (L1), 50-56 (L2) and 89-97 (L3) in the light chain variable domain and 31-35 (H1), 50-65 (H2) and 95-102 (H3) in the heavy chain variable domain; Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md. (1991)) and/or those residues from a “hypervariable loop” (for example residues 26-32 (L1), 50-52 (L2) and 91-96 (L3) in the light chain variable domain and 26-32 (H1), 53-55 (H2) and 96-101 (H3) in the heavy chain variable domain; Chothia and Lesk J. Mol. Biol. 196:901-917 (1987)). “Framework” or “FR” residues are those variable domain residues other than the hypervariable region residues as herein defined.
It should be noted that, in the art, more than one system for numbering of amino acid residues is commonly used. The CDRs above are described and numbered according to the Kabat numbering scheme (Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md. (1991)) but sequential numbering may also be used. Sequential and Kabat numbering are identical for the entire LT1009 light chain, and up to position 52 in the LT1009 heavy chain. In the heavy chain (VH), according to Kabat numbering there is a single residue insertion after position 52, a three-residue insertion after position 82 and a four residue insertion after position 100. Thus residues may at times be seen to be numbered 52A, 100A, 100C etc. to reflect these insertions according to the Kabat system.
The hypervariable regions in each chain are held together in close proximity by the FRs and, with the hypervariable regions from the other chain, contribute to the formation of the antigen-binding site of antibodies (see Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md. (1991), pages 647-669). The constant domains are not involved directly in binding an antibody to an antigen, but exhibit various effector functions, such as participation of the antibody in antibody-dependent cellular toxicity.
A “vector” or “plasmid” or “expression vector” refers to a nucleic acid that can be maintained transiently or stably in a cell to effect expression of one or more recombinant genes. A vector can comprise nucleic acid, alone or complexed with other compounds. A vector optionally comprises viral or bacterial nucleic acids and/or proteins, and/or membranes. Vectors include, but are not limited, to replicons (e.g., RNA replicons, bacteriophages) to which fragments of DNA may be attached and become replicated. Thus, vectors include, but are not limited to, RNA, autonomous self-replicating circular or linear DNA or RNA and include both the expression and non-expression plasmids. Plasmids can be commercially available, publicly available on an unrestricted basis, or can be constructed from available plasmids as reported with published protocols. In addition, the expression vectors may also contain a gene to provide a phenotypic trait for selection of transformed host cells such as dihydrofolate reductase or neomycin resistance for eukaryotic cell culture, or such as tetracycline or ampicillin resistance in E. coli. 